<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            list-style: none;
        }
        #box1{
            width: 800px;
            height: 480px;
            /* background-color: rgb(135, 193, 193); */
            margin: 50px auto; 
            overflow: hidden;
            position: relative;
        }
        #box1>ul{
            /* overflow: hidden; */
            height: 50px;
        }
        #box1>ul>li{
            float: left;
            width: 160px;
            height: 50px;
            background-color: aquamarine;
            box-sizing: border-box;
            /* border: 1px solid #cacaca; */
            text-align: center;
            line-height: 50px;
        }
        #box1>ul>li>ul{
            /* height: 430px; */
            /* display: none; */
            opacity: 1;
        }
        #box1>ul>li>ul>li{
            width: 160px;
            background-color: rgb(254, 227, 191);
            /* z-index: 2; */
            color: #000;
            /* border-left: 1px solid #b4b4b4; */
            /* border-top: 1px solid #b8b8b8; */
            /* border-right: 1px solid #de2b2b; */
            box-sizing: border-box;
        }
        #box1>ul>li:nth-child(1)>ul>li{
            /* display: none; */opacity: 0;
        }
        #box1>ul>li:nth-child(2)>ul>li{
            /* display: none; */opacity: 0;
        }
        #box1>ul>li:nth-child(3)>ul>li{
            /* display: none; */opacity: 0;
        }
        #box1>ul>li:nth-child(4)>ul>li{
            /* display: none; */opacity: 0;
        }
        #box1>ul>li:nth-child(5)>ul{
            /* display: none; */opacity: 0;
        }
        #box1>ul>li:nth-child(1):hover{
            background-color: rgb(254, 227, 191);
            color: #b4b4b4;transition: all 1s;
            /* border-left: 1px solid #b4b4b4; */
            cursor: pointer;
        }
        #box1>ul>li:nth-child(2):hover{
            background-color: rgb(254, 227, 191);
            color: #b4b4b4;transition: all 1s;
            /* border-left: 1px solid #b4b4b4; */
            cursor: pointer;
        }
        #box1>ul>li:nth-child(3):hover{
            background-color: rgb(254, 227, 191);
            color: #b4b4b4;transition: all 1s;
            /* border-left: 1px solid #b4b4b4; */
            cursor: pointer;
        }
        #box1>ul>li:nth-child(4):hover{
            background-color: rgb(254, 227, 191);
            color: #b4b4b4;transition: all 1s;
            /* border-left: 1px solid #b4b4b4; */
            cursor: pointer;
        }
        #box1>ul>li:nth-child(5):hover{
            background-color: rgb(254, 227, 191);
            transition: all 1s;
            color: #b4b4b4;
            /* border-left: 1px solid #b4b4b4; */
            cursor: pointer;
        }
        #box1>ul>li:nth-child(1):hover>ul>li{
            opacity: 1;
            transition: all 1s;z-index: 2;
        }
        #box1>ul>li:nth-child(2):hover>ul>li{
            opacity: 1;
            transition: all 1s;z-index: 2;
        }
        #box1>ul>li:nth-child(3):hover>ul>li{
            opacity: 1;
            transition: all 1s;z-index: 2;
        }
        #box1>ul>li:nth-child(4):hover>ul>li{
            opacity: 1;
            transition: all 1s;z-index: 2;
            display: block;
        }
        #box1>ul>li:nth-child(5):hover>ul{
            opacity: 1;
            transition: all 1s;
            z-index: 2;
            display: block;
        }
        #box1>ul>li>ul>li:hover{
            background-color: rgb(75, 242, 133);
            /* transition: 1s all; */
            color: #000;
            /* border-left: 1px solid #b4b4b4; */
        }
        #box1>div{
            width: 800px;
            height: 100px;
            background-color: rgb(254, 227, 191);
            position: absolute;
            opacity: 0;
            z-index: 0;
            pointer-events: none;/* 让这个 div 不响应鼠标事件 */
        }
    </style>
</head>
<body>
    <div id="box1">
        <ul>
            <li>我的手机
                <ul>
                    <li>苹果手机</li>
                    <li>凤梨手机</li>
                </ul>
            </li>
            <li>你的手机
                <ul>
                    <li>苹果手机</li>
                    <li>凤梨手机</li>
                </ul>
            </li>
            <li>谁的手机
                <ul>
                    <li>苹果手机</li>
                    <li>凤梨手机</li>
                </ul>
            </li>
            <li>他的手机
                <ul>
                    <li>苹果手机</li>
                    <li>凤梨手机</li>
                </ul>
            </li>
            <li>手机在哪
                <ul>
                    <li>苹果手机</li>
                    <li>凤梨手机</li>
                </ul>
            </li>
        </ul>
        <div>

        </div>
    </div>
</body>
</html>